The present invention relates to a method for manufacturing a plastic window and a plastic window.
Japanese Patent Application Publication No. H02-227224 discloses a conventional plastic window. The plastic window includes a transparent body, a film, and a frame. The transparent body is of a plate shape and has on the opposite sides thereof a first surface and a second surface. The transparent body is made of transparent resin. The film includes a transparent base having a sheet shape and a hard coating formed on the surface of the base. The film is provided on the first surface of the transparent body in an integral manner. The frame is made of resin and provided with the transparent body in an integral manner. The frame covers the end surface of the transparent body, the peripheral edge of the first surface of the transparent body including the peripheral edge of the film, and the peripheral edge of the second surface of the transparent body.
The plastic window is manufactured as follows. In the preparation step, the first mold having the first mold surface, the second mold having the second mold surface, and the third mold having the third mold surface are prepared. The first mold surface and the second mold surface cooperate to form a first cavity having a plate shape. The third mold surface and the first mold surface cooperate to form a 25 second cavity having a product shape. In the film preparation step, the film is prepared. In the placement step, the film is placed on the first mold surface.
Next, in the first injection step, the first mold and the second mold are closed and the first molten resin is injected into the first cavity, with the result that an intermediate product is produced. The intermediate product is made including the transparent body made of solidified transparent resin and the film that is provided with the first surface of the transparent body in an integral manner.
Next, in the second injection step, after the first mold and the second mold are opened, the first mold and the third mold are closed and the second molten resin is injected into the second cavity, with the result that a resin frame is formed with the intermediate product in an integral manner. Thus, the plastic window is completed.
In the plastic window, the hard coating of the film protects the first surface of the transparent body. The above-described manufacturing method permits the film to be provided easily on the first surface of the transparent body.
It is conceivable that a conductive part that produces heat or emits light and a bus bar through which electric current flows to the conductive part are added to a plastic window in order to add defogging and ice melting functions, and to improve the decoration of the transparent body.
In this case, the conductive part and the bus bar may be provided directly in the transparent body by printing. However, the resin transparent body may be not only of a plated shape, but also of a curved shape. However, it is difficult to provide a conductive part and a bus bar on a curved transparent body.
It is also conceivable that in the film preparation step of the conventional plastic window manufacturing method, a film having a base on which a conductive portion and a bus bar are formed is prepared. In this case, a conductive portion and a bus bar may be provided easily on the first surface of a transparent body that forms an intermediate product and has a curved shape.
In such a plastic window, however, the exposure of the bus bar on the second surface side of the transparent body degrades the appearance of the plastic window. In order to prevent the exposure of the bus bar, an opaque cover may be provided on the second surface, or alternatively an additional step for coloring the transparent body with opaque color may be performed, which only results in difficulty in the manufacture of the plastic window and hence in increased production cost.
The present invention which has been made in light of the problems mentioned above is directed to providing a method for manufacturing a plastic window which has a good appearance and permits a conductive portion and a bus bar to be easily provided and reduction of the production cost. The present invention is also directed to providing the plastic window.